Which of the following is not component of acinus-

Pulmonary lobule is not a component of acinus, rather cluster of 3-5 terminal bronchioles with acinus form pulmonary lobule. Respiratory tract anatomy Progressive branching of bronchi forms bronchioles. Further branching of bronchioles leads to terminal bronchioles. Terminal bronchiole emanate into respiratory bronchioles. Respiratory bronchioles proceed into the alveolar ducts, with immediately branch into alveolar sacs (alveoli). The part of lung distal to the terminal bronchiole is called acinus, i.e., respiratory bronchiole, alveolar duct and alveolar sac. A cluster of three to five terminal bronchioles, each with its appended acinus, is usually referred to as pulmonary lobule So, pulmonary lobules include a cluster of three to five terminal bronchioles with its respiratory bronchioles, alveolar ducts and alveolar sacs.